An initial and seemingly significant objection to the notion of describing and explaining the phenomenon of translation might well be that the whole of the process (with the obvious exception of the physical aspects of reading and writing) takes place in the mind of the translator and, given that we have, therefore, no direct access to it, we shall be forced back into precisely the unsatisfactory kind of description of the product which we have been saying that we wish to avoid.
We would counter this by pointing out that it is perfectly legitimate to build up a model on the basis of inferences drawn from an objective study of the product. Indeed, such an approach would constitute no more than a special instance of the classic engineering problem of the‘black box' which contains a mechanism which converts input into output but is otherwise totally inaccessible. How is it possible, in such a case, to specify the nature of the mechanism? The solution is to 'work back' from the output of the mechanism (the product) and make a set of statements about the necessary characteristics of the system itself (the process), i.e. to make use of the logical process of induction.
This analogy, however, does not fit the process of translation exactly, since we do have a degree of access to it through the substantial insights we have into the workings of our own minds. This being the case, it should be possible by introspection (i.e by adopting a deductive approach to the problem), to build a model of what we ourselves are doing when we translate.
Ultimately – as the development of psychology has shown – a multiple approach, involving both induction and deduction in a cyclic investigation, is more likely to be revealing than the strict adherence to either induction or deduction alone (see Figure 1).
We might illustrate this by taking up another issue which has exercised translation theorists over a very long period indeed; the problem of the size of the unit of translation. The question 'What is the unit of translation?' resolves itself all too readily into a search for the answer to the question 'What ought the unit of translation to be?' The notion 'unit of translation' - sometimes written 'UT' - has been defined in these terms:
The smallest segment of an SL [source language] text which can be translated, as a whole, in isolation from other segments. It normally ranges from the word through the collocation to the clause. It could be described as 'as small as is possible and as large as is necessary' (this is my view), though some translators would say that it is a misleading concept, since the only UT is the whole text.